Process for the manufacture and production of anthraquinone intermediates



,. the corresponding leuco 1.4 diamino-anthra Patented Sept. 30, 1930 UNITED STATES- PATENT OFFICE WILLIAM WYND'HAM TATUM, OF MANCHESTER, ENGLAND, ASSIGNOR T0 BRITISH DY E- STUFFS CORPORATION LIMITED, OF MANCHESTER, ENGLAND PROCESS FOR THE MANUFACTURE AND PRODUCTION OF ANTHRAQUINONE INTERMEDIATES v No Drawing. Application filed February 10, 1926, Serial No. 87,448, and in Great Britain January 1 1-, 1926.

This invention relates to the manufacture of anthraquinone intermediates; and it comprises a methodof producing 1.4 diaminoanthraquinone and its derivatives wherein quinone is converted into a salt and this salt heated With nitrobenzene, the salt being frequently formed by treating the leuco body with an acid at a lower temperature in the presence of the same nitrobenzene which is subsequently used as an oxidant at a higher temperature; all as more fully hereinafter set forth and as claimed.

Leuco 1.4 diamino-anthraquinone and its various substituted derivatives can be oxidized to the corresponding 1.4 diamino-anthraquinone bodies by heatin with nitrobenzene. Ihave however foun that the oxidation goes on more smoothly with production of better yields of purer products and at a lower temperature if a salt of the leuco body rather than the free base be so heated.

At low temperatures, the nitrobenzene does not oxidize the leuco bodies and the salts may be conveniently formed in the presence of nitrobenzene; the mixture of the saline body formed and of the nitrobenzene being subse- In the described action the nitro body used dizing body is essential and nitrobenzene acts acts both as a solvent and as an oxidant. The presence of an organic solvent and of an oxiin both capacities. Other oxidizing agents may however be used in addition or substitution.

In the co-pending application Serial No. 87,433 of Shepherdson, Tatum and Bunbury there is descrlbed a method of obtaining derivatives of 1:4 diaminoanthra uinone directly from leuco-1: 4-diaminoant raquinone by treating the latter with the appropriate reagei-lt (benzoyl chloride, chlorine, etc.)-. in the presence of an oxidizing solvent such as nitrhbenzene. The leuco-1:4-diaminoanthravention is not limited to the oxidation of leuco dianiino-anthraquinone itself, but ap plies also to derivatives of leuco 1.4-diaminoanthraquinone such as (1) Leuco 1.4-dimethyl-diamino-anthraqumone.

OH NH.CH

NiELCHl (2) Leuco-5-hydroxy-8-amino-1.4-dimethylaminov-anthraquinone,

B:N on neon:

OH on N .CHa

(3) Leuco-5-hydroxy 1.4 dimethyldiamino-anthraquinone.

(4-) Leuco- 5.6 dihydroxy-1.4-dimethyldiamino-'anthraquinon e,

The following are examples further illustrating the nature of my invention, but the invention is not limited to the particular details of the examples. The parts stated are by weight.

EwampZe.1.-Prepamtion of lih-dz'amino-anthmguino'ne hydrochloride from leuco 1.4 diamz'no-anthmquinone hydrochloride 100 parts of leuco 1.4-diamino-anthraquinone are suspended in 500 parts of nitrobenzene and treated at a temperature of 2060 C., with a current of hydrochloric acid gas. The brown suspension changes in colour with evolution of heat to, greenish yellow, and

i then to brownish yellow. When there is no further rise in temperature, and a test sample is insoluble in an excess of cold nitrobenzene, the conversion to leuco hydrochloride is complete. Oxidation is then carried out by heating to 110140 C. for one hour. 1.4-diamino-anthraquinone hydrochloride The salt form of a leuco 1: 4 diamino anthraquinone in the presence of nitrobenzene.

- 5. The process of preparing 1:4 diamino anthraquinones which comprises heating a leuco 1: 4 diamino anthraq uinone hydrochloride in the presence of mtrobenzene.

In testimony whereof I have hereunto affixed my signature.

obtained is filtered off and freed from nitro- WILLIAM WYNDHAM TATUM.

benzene.

By boiling with alkali the product obtained in the above example, pure 1.4-'diam ino-anthraquinone is liberated, or alternatively, the nitrobenzene filter cake of leuco 1.4 diamino anthraquinone hydrochloride may be steam distilled in the presence of alkali to give the free base.

Example 2.-Prepardt ion of 5-h ydrowy-8- amino 1 .4 dimetkyl diam/m0- anthmg'wm- 01w hydrochloride 100 parts of leuco hydroxy-amino-dimethyldiamino-anthraquinone, which can be obtained, for example by warming leuco-diamino-anthrarufin 'or leuco diamino-chrysazin with methylamine on the water-bath, are suspended in 600 parts of nitrobenzene and converted into the leuco hydrochloride by passing in hydrochloric acid gas. The brown sus ension is then oxidized by heating at 130 3 G; or one hour, and the resultant hydrochloride of hydroxy-amino-dimethyldiamino-anthraquinone filtered ofi' and dried.

This compound may be conveniently converted into the free base by boiling with dilute alkali, filtering, washing alkali free, and drying.

5-hydroxy-8-amino-L4 dimethyldiaminoanthraquinone forms a blue powder, insoluble in water but dissolving with a purple colour in dilute mineral acids. The solution in acetic acid is blue, while concentrated sulphuric acid yields a reddish brown solution, which changes to blue on addition of boric acid. An aqueous suspension of the new compound dyes acetate silk in bright greenish blue shades.

I claim: I

1. The process of preparing diamino anthraquinones which comprises converting a leuco diamino 'anthraquinone into its salt form and thereafter heating it in the presence of an organic solvent and an oxidizing agents 2. The process of preparing diamino anthra uinones which comprises heating the salt orm of leuco derivatives of diamino-anthraquinones in the presence of an organic solvent having oxidizing properties.

3. The process of preparing 1:4 diamino anthraquinones which comprises heatin a leuco 1:4 diamino anthraquinone hy rochloride in the presence of an organic solvent having oxidizing properties.

4. The process of preparing 1 4 diamino anthraquinoneswhich comprises heating the 

